Convertible pulse jet and ram jet engine



y 15, 1956 .1. 5. WINTER ET AL 2,745,243

CONVERTIBLE PULSE JET AND RAM JET ENGINE 2 Sheets-Sheet 1 Filed Oct. 12, 1950 1 FIG. I.

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No: [I (\l w r I E I T. [C o q I I o f l l m f L Q N 3 \J m \q i m #1 L A N I H O Q I INVENTORSI v E JOHN S. WINTER 1 BY GEORGE W. KALLAL 1 8 JAMES J. MAZZONI I @M Y &A/\ yfij gl ATTORNEYSL y 15, 1955 I .1. 5. WINTER ET AL CONVERTIBLE PULSE JET AND RAM JET ENGINE Filed Oct. 12, 1950 2 Sheets-Sheet 2 RL... E mN H E m A N NWKM R M w J T I S 0/ A wm m JO EMU G w Y @W B end of the pulse jet engine.

United States Patent CONVERTIBLE PULSE JET AND RAM JET ENGINE John S. Winter, Florissant, George W. Kallal, Overland, and James J. Mazzoni, Richmond Heights, Mo., assignors to McDonnell Aircraft Corporation, St. Louis,

Mo., a corporation of Maryland Application October 12, 1950, Serial No. 189,736

3 Claims. (Cl. 60-35.6)

Another object of the invention is to provide a control means in-a pulse jet engine that will permit the engine to operate in a manner similar to that of a ram jet engine. The invention consists in the provision of a pulse jet engine having either a drum type inlet valve or a bulk-head type of valve which includes means for rendering the inlet valve inefiective so that the engine may operate thereafter in a manner similar to a ram jet engine.

In the drawings: vFig. l is a longitudinal sectional view of a' pulse jet engine embodying the invention,

Fig. 2 is a sectional view taken substantially along the line 2-2 of Fig. l, a

Fig. 3 is a sectional view taken substantially along the line,33 of Fig. 1,

. Fig. 4 is a sectional View taken substantially along the line 4-4 of Fig. l,

Fig.'5 .is a perspective view of the drum typevane and reed valve shown in section in Fig. 2,

.Fig. 6 isa longitudinal sectional view of a modified form of pulse jet engine,

Fig. 7 is a sectional view taken substantially along the line 7- 7 of Fig. 6, parts being omitted, I

Fig.' 8 is a sectional view taken along the line 8-8 of Fig. 6,

Fig. 9 is a sectional view of a modified form of a vane and reed valve; and

Fig. 10 is an end view of the reed shown in Fig. 9.

The invention is embodied in the structure illustrated in Figs. 1 through 5 in which the numeral 1 designates the casing for a pulse jet engine made up of a plurality of tubular sections 2, 3 and 4. Section 2 constitutes the combustion chamber for the engine to which section 3 is connected. Section 3 is tapered, section 4 being connected thereto and defining the exhaust nozzle of the engine.

A drum type of vane and reed valve 5 is connected to the forward end of section 2. A cowling 6 is connected to the drum valve and constitutes the air inlet A fuel manifold 8 having jet nozzles 8' of suitable type is mounted in section 2 aft of the drum valve for introducing fuel into the engine, fuel being forced therein under pressure by a pump (not shown). A suitable conduit 7 is connected between the manifold and the pump.

The drum type vane and reed valve 5 may include longitudinal divider vanes 50 forming radial sections in which two cooperating valve reeds 51 are movably mounted. The reeds 51 are normally urged to closed positions and open'upon pressure differential conditions across the same. Circumferential dividers 52 are shown to stiffen the drum. I H; 7

An annular air deflector 9 is mounted on section 2 that flares outwardly and forwardly for the purpose of directing air into the drum valve and thence into the engine. The air deflector is provided with a cylindrical portion 10 welded to section 2. A sleeve valve 11-is slidably mounted in cowling 6 and has a length somewhat greater than the axial length of the drum valve 5. The sleeve valve 11 controls the flow of airthr'ough drum valve 5. A butterfly valve 12 is rotatably mounted in the cowling andmay be actuated by a lever 13 (Fig. 3) which is connected by suitablemechanism to a manuallyoperated control member (not shown). the engine as a ram jet requires that the valve 12 be opened (dotted position of Fig. 1) and sleeve valve 11' be moved rearwardly (dotted position) to close valve 5.

Obviously, pulse jet operation necessitates forward set-' ting of sleeve" valve 11 and closing of valve- 12. The

sleeve is operated by suitable mechanism under control:

from the pilots station in-the aircraft. Such mechanism may be a 'cable 53 attached to the sleeve 11 at anchor' 54. One reach of the cable may be run through a pulley 55, the other reach (not shown) being runto a'pulley on thebody of valve 5. A spark pluy 14 is mounted in section 2 for initially igniting the fuel introduced therein through the manifold 8.

The above described engine is started as a pulse jet and during starting the sleeve 11 is inthe full line position indicated in .Fig. 1: so that the drum valve 5 is free to function. The butterfly valve 12' is in closed position so that all air entering the casing section 2 must pass through the. drum vane and reed valve 5. Fuel is then admitted to section 2 of the casing. through jet orifices.8"

formed. in. manifold 8 and is ignited by the'spark plug 14.- The deflector causes air to pass through't'he vane and" r'eed'valve 5 where. it is'mixed with the fueL'after-which:

the combustion process takes place. The enginenow operates as an ordinary pulse'jet so that static 'thr'ust Will be developed. 1 H

preventing flow through the vane and reed valve 5. The air flow through drum valve 5 is effectively checked because sleeve 11 is positioned in alignment therewith and since it also extends past the right hand end of the drum in abutment with the manifold 8, only a small amount of air passes therethrough. The butterfly valve 12 is then moved to the open, or dotted line position so that the engine will operate as a ram jet engine. At high speeds the etficiency of a ram jet engine exceeds that of a pulse jet. For this reason the type of operation most suitable for maximum efficiency can be selected by the pilot of the aircraft in which the engine is mounted. It is possible to start the aircraft from rest position and, when the critical speeds have been attained, the engine can be converted ino a valveless pulse jet or a ram jet engine so that no loss of overall efliciency will be experienced.

A modified form of the invention is illustrated in Fig. 6 in which the engine casing is designated by the numeral 15 and which consists of a tubular section 16, a tapered section 17, and a tail piece tubular section 18, the latter constituting a discharge nozzle for the engine. An inlet section 19 is connected to the casing section 16 and suitable cowling 20 is secured to the forward end of the inlet section 19. A tubular member 21 is disposed with- Patented May 15, 1956 Operation of irrsection 19' andterminatesi-aneudisc-like plate or bracket 22 mounted in section 19, the bracket being disposed a short distance from the joint between sections 17 and 19. The tubular member 21 constitutes an air inlet connected between: the cowling and. the bracket.22.

A ane and reed type valve 23" is mounted: at the discharge end of the tubular member 21. This valve; is provided with stud brackets 24;v the stud? portion extending throughsthei bracket 22'. The stud portionof brackets 24: has; an: aperture 25" therein for receiving a pin 26. Therearefour stud brackets illustrated,.the pins therefore being actuatedzby suitable solenoids 27 whose function is to hold pin 26; in aperture 25 andto withdraw ittherefrom when the-reed andvanevalve 23? isto be jettisoned. The solenoids. may be; secured to bracket 22 as a matter of convenience:

A fuel manifold 28 circumscribes the tubular member 21- for the purpose of introducing fuel into the air stream enteringz said; member. The manifold is connected to a suitable source of pressurized fuel supply through a condilit 29. A spark plug 30 is mounted in the casing sectionzl9 aft of the reed and vane valve for initially igniting thev fuel introduced into the engine casing.

As illustrated, the engine operates as a pulse jet. Since pulsezjets" lose their operating efliciency at critical speeds for reasons set forth above, the: engine must bev converted into: a valveless pulse jet or ram jet if speeds higher than critical are: to be attained by the jet engine. In the instant' disclosure the reed and vane valve 23 is jettisoned by; withdrawing pins 26 from the stud brackets 24.

Thereafter the engine operates as a valveless pulse jet or ram jet engine so that maximum etficiency will be attained: by'the engine at higher speeds. Another modified form of the invention is illustrate in-Figs'. 9 and 10; Figure 9 shows a section of a reed and? vane valve in which 31 is the vane portion of the valve andz32 the reed portion thereof; The vane is constructed in a conventional manner and the reed is secured thereto. inthe same manner. However, the reed is ground as at? 33 in order to reduce the section: thereof. The purpose: of this reduced section is to stimulate breakage ofthe vibrating portion ofthe reed. after a predetermined amount of time. mountediwillhave attained critical speeds when breakage occurs so that the reeds may then be jettisoned, thus enabling the engine. to operate as a valveless pulse jet orran jet. engine. The vanes remaining in the engine will impede the airflow through the tubular: member 21, butthe essential portion of the valve will be removed therefrom. Theengine will not attain speeds as great The aircraft inv which the engine is.

the engine is operating as a ram jet; and means for preventing flow of air into said cowling while the engine is operatingas a pulse jet.

2. A jet engine comprising a casing, a tubular valve connected to one end of said casing, anair inlet cowling provided with an air inlet tube connected to said tubular valve, a valve member mounted insaid air inlet tube to control the flow of air into the casing selectively for ram jet operation and to cut off the flow of air for pulse jet operation, a sleeve slidably mounted insaid air inlet tube to surround said valve member, said sleeve beingmovable to a position opposite said tubular valve to prevent flow of air through said tubular valve while the engine is operating as a ramjet; and means for directing airinto said tubular valve while the engine is operating as a-pulse-jet.

3. A convertible pulse jet or ram jet engine comprisinga casing, an air flow control valve in said casing, means for introducing fuel into said casing, means for igniting said fuel, valve elements in said control valve reversibly movable to open and closed position in response to pressure for causing said engine'to operate as a pulse jet engine, means movable between a position admitting air through said control valve elements-for engine operation as apulse jetand a position preventing airflowthrough said control valve elements for engine operation as a ram. jet, and valve control means for admittingair for ram jet operation.

References Cited in the file of this, patent UNITED STATES PATENTS 1,854,615 Lasley Apr. 19, 1932 2,397,357 Kundig Mar.v 26, 19.46 2,505,757 Dunbar. et al. May 2, 1950 2,635,421 Blum- Apr. 21, 1953, 2,644,396 Billman July 7, 1953 2,677,232 Collins May 4,. 1954 FOREIGN PATENTS.

590,177 Great Britain July 10, 1947' 614,696 Great Britain Dec. 20, 1948 

